Exploiting the New Frontier of Gravitational-Wave Astronomy
Frederick J. Raab
LIGO Laboratory, California Institute of Technology

The first direct detections of gravitational waves, announced by the LIGO Scientific Collaboration and the Virgo Collaboration, opened the vast new frontier of gravitational-wave astronomy. The first detections of merging black holes confirmed that Einstein's General Theory of Relativity gives a good description of the most extreme spacetimes ever encountered. GW170817 provided the first gravitational-wave detection of the most extreme state of matter, the merger of two neutron stars, followed by the rich electromagnetic observations of the resulting kilonova. Extracting the best science from future observations will require building out the international network of gravitational-wave detectors to optimize localization of the sources and to recover full polarization information from events and providing fast and accurate alerts for electromagnetic and astro-particle follow-up observations. From the first observations of merging black holes, we extrapolate that such mergers occur several times per hour somewhere in the observable universe. This motivates the continuation of the evolution of gravitational-wave detectors with greater sensitivity, eventually probing mergers of black holes formed by the first generations of stars, deeply probing the nature of extreme spacetime and the nature of matter at extreme density.